BACKGROUND OF THE INVENTION
[0001] The present invention relates to aqueous alkaline hydrogen peroxide formulations
and in particular to stabilized phosphate-free and boron-free formulations.
[0002] In household laundry bleach, hard surface cleansers, and other cleanser formulations,
aqueous alkaline hypochlorite solutions are typically employed for stain removal and
disinfection. Such formulations are very effective, but chlorinaceous compounds may
interact with dissolved and suspended organic material, forming carcinogens or other
noxious substances. Furthermore, these hypochlorite-based compositions may cause fiber
degradation, and may be incompatible with certain fabric dyes.
[0003] To remedy these disadvantages, manufacturers have developed environmentally benign
alternatives based on acidic aqueous hydrogen peroxide solutions. These compositions
are also fiber-safe and color-safe. Commercially available hydrogen peroxide solutions
typically include a trace amount of phosphorus; the industry, however, promotes the
use of compositions without any additional phosphorus-containing compounds. Furthermore,
hydrogen peroxide (H
2O
2) is a product that is generally acceptable from a toxicological and environmental
standpoint because its decomposition products are oxygen and water.
[0004] Hydrogen peroxide is typically stored with stabilizers since decomposition due to
the presence of catalytically active substances is extremely difficult to prevent.
For this reason, much study has gone into improving the storage characteristics of
hydrogen peroxide and into the dynamics of the stabilization process.
[0005] Mixtures of stabilizers are frequently added to the hydrogen peroxide solution since
the combined effect is sometimes better than the individual stabilizers. Also, other
substances are sometimes added to the solution in order to maintain the surface of
the container, particularly those of aluminum. For example, sulfate and chloride may
degrade a aluminum container, so a small amount of nitrate may be added to the solution
to prevent pitting the surface of the aluminum container.
[0006] After an extensive amount of research on stabilizers, stannates, oxines, and phosphorus-containing
compounds, such as phosphate and phosphonic acid derivatives, appear to be the preferred
stabilizers for hydrogen peroxide containing solutions. For example, tin compounds,
specifically sodium stannate [Na
2Sn(OH)
6], have been known as peroxide stabilizers for many years and are widely used as stabilizers
for acidic solutions (less than about pH 5).
[0007] The performance of these cleaning compositions can be improved, in particular the
bleaching and stain removal, by formulating alkaline products. However, the commercial
use of alkaline formulations has been hindered by the strong tendency of alkaline
H
2O
2 solutions to decompose during storage. For example, under typical storage conditions,
compositions containing a stannate compound may release hydroxyls which increase the
pH and increase the decomposition rate. With excessive decomposition, the cleaning
product loses its efficiency, its cleaning ability, and its storage life (shelf life).
[0008] The stability of aqueous alkaline H
2O
2 solutions has been improved by employing amino methylene phosphonic acid together
with low weight alcohols as the stabilizer system (see, for example, GB 2072643, EP-B
0076166, and WO 91/09807). However, these alkaline compositions still suffer from
decomposition and pH drift (toward an acidic pH), problems which have been addressed
by incorporating cyclohexane 1,2 diamino methylene phosphonic acid and borate compounds
as the buffer and stabilizer (see, for example, WO 93/13012).
[0009] Stable aqueous peroxygen solutions containing perborates and/or hydrogen peroxide
in combination with acids (e.g., boric acid) have been stabilized with water-soluble
carbazole sulfonates, diphenylamine sulfonates or N-phenylamino naphthalene sulfonates
with or without DTPA (diethylenetriamine pentamethylene phosphonic acid). Although
alkaline persalts are employed, the pH of the final solutions are described to be
below 7 due to the addition of acids (see, for example, WO 91/11388).
[0010] However, with increasing concern and stronger restrictions on the addition of phosphorus
and boron compounds into detergent/laundry products, it is preferable to have phosphorus-free
and boron-free formulations without compromising effectiveness, stability, and safety.
[0011] Alkaline peroxygen solutions are described in EP 0376704 in which a phosphonate sequestrant
or colloidal stannic oxide is utilized as a stabilizer for thickened alkaline H
2O
2 formulations. Also described are tin sulphate, sodium stannate, tin dichloride and
tin tetrachloride as compounds which generate colloidal hydrous stannic oxide under
alkaline conditions. However, organic compounds such as stannic oxalate or stannic
tartrate are not disclosed or suggested.
SUMMARY OF THE INVENTION
[0012] In accordance with the invention I found a phosphorus-free and boron-free cleaning
composition comprising an aqueous solution having an alkaline pH and containing an
active ingredient and a tin compound as stabilizer, said active ingredient comprising
hydrogen peroxide or a compound capable of releasing hydrogen peroxide under the conditions
prevailing in use of said composition, which is characterized in that said stabilizer
comprises at least one organic tetravalent tin complex with dicarboxylic acid, hydroxy
carboxylic acid, or tricarboxylic acid. The stabilizers are environmentally safe and
biodegradable. It was found that the combination of organic stannic compounds of di-
and tri-carboxylic acids such as oxalic acid tin IV complexes are significantly more
stable formulations at even higher concentrations than the individual stabilizers
alone.
SPECIFIC DESCRIPTION OF THE INVENTION
[0013] In accordance with the invention, phosphorus-free and boron-free cleaning compositions
comprise alkaline solutions containing hydrogen peroxide and/or a percarbonate, stabilized
with an organic stannate.
[0014] According to the present invention, there is provided a storage stable composition
suitable for use as household bleach and disinfectant compositions. The composition
includes at least one active ingredient, such as an alkaline solution of hydrogen
peroxide, sodium percarbonate, or combinations thereof. Preferably, the composition
has an active oxygen content of between about 0.5% w/w and about 10% w/w. The cleaning
composition also comprises at least one tin IV complex containing stabilizer, such
as an organic stannic compound such as stannic oxalate or stannic tartrate. The composition
typically will also include one or more pH adjusters to maintain an alkaline pH. Optionally,
the composition may also include one or more surfactants, thickening agents, electrolytes,
coloring agents, fragrances, or combinations thereof with other conventional additives.
[0015] As used herein, cleaning composition refers to industrial and household cleaning,
bleaching, and/or disinfectant solutions. These compositions typically include an
active ingredient, one or more stabilizers, one or more buffers, one or more surfactants,
one or more thickening agents, one or more anti-redisposition agents, one or more
coloring agents, and/or one or more fragrances.
[0016] As used herein, hydrogen peroxide refers to the compound
per se, and to compounds which release hydrogen peroxide in solution under the conditions
prevailing in the described process of using the cleaning composition, including but
not limited to urea peroxide, sodium peroxide, calcium peroxide, magnesium peroxide,
and other such compounds known in the art.
[0017] As used herein, the term "stannate" refers to any composition which forms stable
soluble stannic compounds. Exemplary stannates include but are not limited to organic
stannate complexes which are tetravalent tin IV complexes with dicarboxylic acids
(DCA); e.g., of the formula (Sn(DCA)
3)
2-. As used herein, the term "dicarboxylic acids" include for example saturated linear
aliphatic dicarboxylic acids having the formula HOOC(CH
2)
nCOOH where n=0-19 (especially n=0-11) such as oxalic, malonic, succinic, glutaric,
adipic, pimelic, suberic, azelaic, and sebacic acids. Additionally, dicarboxylic acids
also include hydroxy dicarboxylic acids (HCA) such as tartaric, malic, tartronic,
and phloinoic acids; e.g., Sn(HCA)
32-. Dicarboxylic acids are generally described in Kirk-Other's
Encyclopedia of Chemical Technology, (Third Edition), Volume 7, pages 614-628, phthalic acids are described in Kirk-Other's
Encyclopedia of Chemical Technology, (Third Edition), Volume 17, pages 732-777, and hydroxy dicarboxylic acids are described
in Kirk-Other's
Encyclopedia of Chemical Technology, (Third Edition), Volume 13, pages 103-121; all of which are entirely incorporated
herein by reference. Thus the organic stannate complexes include compounds such as
stannic oxalate, stannic tartrate, and the like. The preferred stannates (IV) are
those where the dicarboxylic acids are oxalic, adipic, succinic, glutaric or tartaric
acids, and mixtures thereof.
[0018] Organic stannate complexes also include tin complexes with saturated cyclic dicarboxylic
acids (e.g., 1,4 cyclo hexane dicarboxylic acid; 1,4 cyclo pentane dicarboxylic acid),
saturated cyclic hydroxy carboxylic acids (e.g., 2 hydroxy cyclohexane carboxylic
acid; 2 hydroxy cyclopentane carboxylic acid), benzene dicarboxylic acid, and acids
of the following formulas:

where x = 0-20,
preferably x ≦ 10, more preferably x ≦ 5 (e.g., 0, 1, 2, 3, 4, 5).

where y = 1-20,
preferably y ≦ 10, more preferably y ≦ 5 (e.g., 1, 2, 3, 4, 5).
[0019] Organic stannate complexes also include tin complexes with tricarboxylic acids (e.g.,
citric acid) and alpha hydroxy carboxylic acids (e.g., I, J hydroxy acids such as
lactic acid; I or J hydroxy cyclohexane carboxylic acid). Examples of tin complexes
which may be used in the present invention are found in Gmelin Handbuch der Anorganischen
Chemie, Springer-Verlag, 1975, which is incorporated by reference in its entirety,
especially pages 34-35, 75-81, and 223-227. Examples of such compounds include Sn
2(C
2O
4)
74-; Sn(C
2O
4)
44-; Sn(C
2O
4)
m4-2m; and Sn(IV)oxalate.
[0020] In addition, Sn (II) complexes can be used which are immediately oxidized to the
corresponding Sn (IV) complexes when mixed with H
2O
2 or a compound capable of releasing hydrogen peroxide under the conditions prevailing
in use of the composition of the invention.
[0021] As used herein, pH adjuster refers to any compound used to achieve an alkaline pH
of the cleaning composition, typically above about 7.5, and preferably from about
7.5 to about 11.0. When hydrogen peroxide is the active ingredient, exemplary pH adjusters
include, but are not limited to, an alkali metal hydroxide, such as sodium hydroxide
(NaOH) or potassium hydroxide (KOH); a carbonate or bicarbonate, such as sodium carbonate
(Na
2CO
3) and baking soda (NaHCO
3); or a silicate, such as sodium silicate (Na
2SiO
3), or aqueous NH
3 solution. When the active ingredient is sodium percarbonate, exemplary pH adjusters
include, but are not limited to, non-phosphorus containing acids, including inorganic
acids, such as nitric acid (HNO
3), sulfuric acid (H
2SO
4); or organic acids or salts thereof, such as acetic acid or sodium acetate (NaC
2H
3O
2).
[0022] One skilled in the art will recognize that commercially available hydrogen peroxide
solutions typically include a trace amount of phosphorus and/or boron. As used herein,
the term "phosphorus-free" refers to a solution which does not contain any added compound
which produces a phosphorus ion in solution or adds phosphorus ions to the solution.
The solution will contain less than 15 ppm phosphorus. Likewise, the term "boron-free"
as used herein refers to a solution which does not contain any added compound which
produces a boron ion in solution. The solution will contain less than 1 ppm boron.
[0023] In practice, it is preferable to select the concentration of active ingredient so
that the active oxygen range of the cleaning solution falls between about 0.5% and
about 10%. For example, when hydrogen peroxide is the active ingredient, the active
oxygen content will typically range from about 0.7% to about 4.1% (from about 1.6%
H
2O
2 to about 8.0% H
2O
2 by weight). When sodium percarbonate is the active ingredient, the active oxygen
content will typically range up to about 2% (sodium percarbonate itself is commercially
available with an active oxygen content of 13-15%, but compositions containing it
have lower active oxygen content due to its limited solubility).
[0024] The tin complex is added in the range from about 10 to about 1000 ppm Sn(IV), preferably
from about 20 to about 500 ppm.
[0025] In selecting the amounts of stabilizers, the pH of the solution is preferably taken
into account, the higher the pH, the higher the stabilizer concentration. The pH range
should be alkaline (i.e., above 7), e.g., above about 7.5, preferably between about
8.5 and about 11.0, and most preferably between about 9.5 and about 10.5. The final
pH of the formulation is adjusted by addition of pH adjusters, such as NaOH, KOH,
Na
2SiO
3, NaHCO
3, NH
3, or sodium carbonate. In the case of the use of sodium percarbonate, preferably H
2SO
4, HNO
3, glacial acetic acid or baking soda (NaHCO
3) is employed for pH adjustment.
[0026] A composition according to the invention may also include, as noted above, surfactants.
The concentration of surfactant are selected in the range from about 0.25% to about
25%. These surfactants are believed to improve the extent of wetting of the surface
of the fibers or penetration into the fibers, enhancing the disinfection rate and
bleaching performance. The surfactants may be selected from the group of nonionic
surfactants, such as alkyl ether ethoxylates, amine oxides, alkyl ether sulfates;
or anionic surfactants, such as sodium lauryl sulfate. Such surfactants and the amount
used are known to and within the knowledge of one skilled in the art.
[0027] A composition according to the invention may also include, as noted above, a thickening
agent which is stable to oxidation under alkaline conditions. It has been found that
polymer-based products, such as polyacrylic acid copolymers (e.g. Carbopol 934, 1623,
1610) provide the best stability. Typically, these thickening agents are added in
a concentration of from about 0.25% to about 2.0%. Such thickening agents and the
amount used are known to and within the knowledge of one skilled in the art.
[0028] A composition according to the invention may also include, as noted above, a fragrance
compatible with alkaline cleaning solutions, typically in a concentration of from
about 0.03% to about 0.5% w/w. Such fragrances and the amount used are known to and
within the knowledge of one skilled in the art. Fluorescent whitening agents may also
be added in the amount, for example, of 0.1 to 1.0% by weight.
EXAMPLES
[0029] In the following examples, various compositions were tested and compared according
to a stability rating (in %), as follows:
Accelerated Stability Test (16hrs 96 °C) |
Room Temperature (5 weeks) |
40 °C (5 weeks) |
100-75 |
excellent |
100-95 |
excellent |
100-80 |
excellent |
74-30 |
good |
94-85 |
good |
79-60 |
good |
29-10 |
moderate |
84-75 |
moderate |
59-30 |
moderate |
<9 |
poor |
<74 |
poor |
<29 |
poor |
[0030] The following tests were performed:
Stability Tests
[0031]
1. 96 °C/16 hrs Tests
The formulation (50 ml) is heated at 96 °C in a 50 ml volumetric flask for 16 hrs.
The stability is expressed as the percentage of residual H2O2.
2. 40 °C and 20 °C Tests
The formulations were stored in an oil bath at constant temperature in tightly sealed
polyethylene bottles for a defined storage period (e.g., six weeks) . The stability
is expressed as the percentage of residual H2O2 after the defined storage period.
Soaking Tests
[0032]
1. Soaking in diluted bleach solutions: 50 g of stained cotton swatches were immersed
in 1000 ml of tap water at 20 °C. The corresponding amount of bleaching agents were
added under stirring. After 24 hrs bleaching time, the swatches were rinsed with tap
water and air dried. Brightness (ISO % reflectance; 457 nm) was measured using a Elephro
Data Color 2000 spectrophotometer. Brightness increase is calculated as the percentage
of the brightness gain compared to the initial brightness of the original stained
swatches:

2. Soaking Application with concentrated bleach solutions: 2 x 2 inch stained cotton
swatches were wetted with 10 ml bleach product at room temperature for 30 minutes.
Brightness increase was determined as described above.
Active oxygen was determined by "Iodometric Determination of Hydrogen Peroxide".
EXAMPLE 1: Stability of 2% H2O2 Solutions
[0033]
Table 1
Stabilizers (ppm 100%) |
pH (NaOH) |
Stability (%) 16 hrs, 96 °C |
Na2Sn(OH)6 |
Trisoxalato stannate IV |
|
- |
1000 |
10.0 |
86.8 |
1000 |
- |
10.0 |
71.1 |
EXAMPLE 2: Stability of 3.5% H2O2 Solutions
[0034]
Table 2
Stabilizers (ppm 100 %) |
|
pH (NaOH) |
Stability (%) 16hrs, 96 °C |
Na2Sn(OH)6 |
Na2Sn(C204)3 |
|
100 |
- |
9.5 |
53.2 |
200 |
- |
9.5 |
55.4 |
- |
100 |
9.5 |
88.8 |
EXAMPLE 3: Stability of 5% H2O2 Solutions
[0035]
Table 3
pH(NaOH) |
Na2Sn(C2O4)3, ppm |
Stability; 16hrs, 96 °C |
8.0 |
1000 |
96.9 |
9.0 |
1000 |
83.8 |
9.5 |
1000 |
62.7 |
10.0 |
1000 |
30.8 |
EXAMPLE 4: Stability of 2% H2O2 Solutions
[0036]
Table 4
pH(NaOH) |
Stabilizer |
Stability; 15 weeks, 40 °C |
10.5 |
1000 ppm Na2Sn(C2O4)3 |
85.8 |
10.5 |
1000 ppm Na2Sn(OH)6 |
75.3 |
EXAMPLE 5: Stability of 2% H2O2 Solution (16hrs, 960C)
[0037]
Table 5
pH |
Na2Sn(C2O4)3 (ppm) |
Alkali Source |
Stability (%) 96 °C, 16 hours |
10.0 |
1000 |
Na2SiO3 |
12.2 |
10.0 |
1000 |
Na2CO3 |
20.6 |
9.8 |
1000 |
Na2CO3 |
38.7 |
EXAMPLE 6: Stability of 5% H2O2 Solutions
[0038]
Table 6
pH (NaOH) |
Stabilizer (ppm) |
Stability (%) 16 hrs, 96 °C |
9.5 |
Na2Sn(OH)6 (100) |
53.2 |
9.5 |
Na2Sn(OH)6 (200) |
55.4 |
9.5 |
Na2Sn(C2O4)3 (100) |
88.8 |
9.5 |
Na2Sn(glut.)3 (100) |
86.9 |
9.5 |
Na2Sn(adipic)3 (100) |
89.1 |
9.5 |
Na2Sn(tartaric)3 (100) |
89.2 |
9.5 |
Na2Sn(citric)3 (100) |
84.1 |
[0039] The acids in the stabilizers in tables 1-6 can be substituted by other acids in the
tin IV complex.
EXAMPLE 7: Stability of 3.5% H2O2 with carboxylic acids at pH 10.0 (NaOH)
[0040]
Stabilizer (conc. in ppm) |
Stability (%) 16 hrs, 96 °C |
oxalic acid, 1000 ppm |
< 1 |
adipic acid, 1000 ppm |
1.9 |
citric acid, 1000 ppm |
< 1 |
tartaric acid, 1000 ppm |
< 2.1 |
none |
< 1 |
[0041] The above data show that the acids alone do not stabilize H
2O
2, it is only the tin IV complex with the acid that stabilizes H
2O
2.
EXAMPLE 8: Liquid Bleach Formulation (P-free), thickened
[0042]
- 7.0g
- H2O2 50%
- 0.8g
- Carbopol 934
- 0.05g
- Stabilizer (Na2Sn(C2O3)3)
- 3.09g
- Surfactant (amine oxide)
- Balance
- NaOH (pH 10) + DI water to 100g
[0043] Stability (16hrs, 96 °C) : 31.1%
Example 9: Liquid bleach formulation
[0044] 70 g H
2O
2 50% unstabilized
0.1g Na
2Sn(C
2O
4)
3
3.0g Lauramine oxide (30%, Stepan Ammonyx LO)
1.0g Polyvinylpyrrolidone (BASF K30)
2.0g Alcohol ethoxylate(Shell 23-5)
Balance to 100g: NaOH(pH 10.0) and DI water
Stability at 40 °C for 8 weeks: 91.3%
[0045] Table 7 displays the results of a soaking test at a liquor ratio of 1:20 obtained
with a commercial color-safe bleach product and the formulation of example 9 at pH
10 with the same H
2O
2 content (3.5%) . With the exception of cocoa stain, significantly higher brightness
levels could be achieved with the formulation of example 9. The reason for the only
moderate response to bleaching/stain removal of the cocoa stain is its lipophilic
character.
Table 7
Comparison of bleaching results (% stain removal); soaking tests 16 hrs, RT., liquor
ratio 1:20, 240 ppm AO (active oxygen) |
Stain |
Commercial color-safe bleach with 3.5% H2O2 |
Formulation acc. Example 9 |
Wine |
31.9 |
47.0 |
Tea |
8.0 |
20.1 |
Grass |
91.8 |
130.7 |
Blueberry |
59.8 |
92.4 |
Cocoa |
23.5 |
27.7 |
[0046] The data displayed in Table 8 clearly show that the alkaline formulation (pH 10)
of example 9 outperforms the acidic (pH 4.5) commercial color-safe bleach. Typically,
three times higher brightness gains were achieved with the formulation of example
9.
Table 8
Comparison of bleaching results (% stain removal); direct application of undiluted
products, RT. 30 min. |
Stain |
Commercial color-safe bleach with 3.5% H2O2 |
Formulation acc. Example 9 |
Wine |
34.5g |
95.80 |
Tea |
12.3 |
40.0 |
Grass |
62.6 |
134.6 |
Blueberry |
56.7 |
157.6 |
Cocoa |
38.3 |
97.3 |
[0047] Preparation of tris oxalato stannate IV: To 100 g of a 4.4% sodium stannate solution, 5.4 g of oxalic acid are added at Rt.
The pH is then adjusted to 4.2 with NaOH. The solution is then added to the H
2O
2 solution before pH adjustment to the alkaline range.
[0048] Preparation of tris tartrato stannate IV: To 10g of sodium stannate in 1000g DI water, 20.5 g of tartaric acid are added slowly.
The pH is adjusted to 4.2 with NaOH.
[0049] Preparation of tris adipato stannate IV: Due to the low solubility of adipic acid the complex is preferably formed in-situ.
To 1000g 5% H
2O
2 solution 0.9 g of adipic acid is added, then slowly 8.8 g of a 5% sodium stannate
solution is added slowly. The pH of the peroxide solution is then adjusted to the
desired level with an alkaline compound.
Example 10: 5% H2O2 solution
[0050] To 50g of 5% unstabilized H
2O
2 400g of deionized water were added. Then 23.0 g of tris oxalato stannate IV stabilizer
solution (described under 1) is added. The pH of the H
2O
2 solution is adjusted with 5% NaOH to 10.0 and deionized water is added to reach a
total of 500.0g. Stability at 96 °C for 16 hrs is 30.8%.
Example 11: 2% H2O2 solution
[0051] To 20g of 50% unstabilized H
2O
2 solution, 450g of deionized water is added, then 23.0g of tris oxalato stannate IV
solution is added. The pH of the solution is adjusted with 5% NaOH to 10.0 and DI
water is used to reach a total of 500g. Stability at 96 °C for 16 hrs is 86.8%.
Example 12: 5% H2O2 formulation, thickened
[0052] To 900g of 5.5% H
2O
2 containing 1000 ppm trisoxalato stannate IV, 100g of a 30% lauramine oxide solution
was added. Then 8g of Carbopol 934 polymer were added under vigorous stirring. The
pH of the mixture was adjusted to 10.0 with 10% NaOH.
[0053] The sample was split and stored in closed polyethylene bottles at room temperature
(21-24 °C) and 40 °C, respectively, over a period of 3 months. The active oxygen content
was determined by titration with 0.1 N cerium sulfate.
[0054] The results (residual H
2O
2, AO loss in parenthesis) are as follows:
Storage Time(days) |
RT. |
40 °C |
0 |
4.88(0) |
4.88(0) |
7 |
4.82(1.2) |
- |
20 |
- |
- |
62 |
- |
4.58(6.2) |
95 |
4.64(4.9) |
4.15(14.9) |
[0055] The stability of the formulation at 96 °C for 16 hrs was 68.5%.
[0056] Further variations and modifications of the foregoing will be apparent to those skilled
in the art and such variations and modifications are attended to be encompassed by
the claims that are appended hereto.
1. A phosphorus-free and boron-free cleaning composition comprising an aqueous solution
having an alkaline pH and containing an active ingredient and a tin compound as stabilizer,
said active ingredient comprising hydrogen peroxide or a compound capable of releasing
hydrogen peroxide under the conditions prevailing in use of said composition, characterized
in that said stabilizer comprises at least one organic tetravalent tin complex with
dicarboxylic acid, hydroxy carboxylic acid, or tricarboxylic acid.
2. A composition according to claim 1, characterized in that it contains said active
ingredient in a quantity corresponding to an active oxygen content in said composition
from about 0.5% w/w to about 10% w/w.
3. A composition according to claim 1 or 2, characterized in that said dicarboxylic acid
is selected from the group consisting of oxalic acid, succinic acid, adipic acid,
glutaric acid, tartaric acid, and mixtures thereof.
4. A composition according to claim 1 or 2, characterized in that said tricarboxylic
acid is citric acid.
5. A composition according to claim 1 or 2, characterized in that said hydroxy carboxylic
acid is lactic acid.
6. A composition according to any of the claims 1 to 5, characterized in that it contains
further a pH adjuster in a quantity sufficient to produce a pH from about 8.5 to about
11, preferably from about 9.5 - 10.5.
7. A composition according to any of the claims 1 to 6, characterized in that the concentration
of said tin complex is between about 10 ppm and about 1000 ppm.
8. A composition of any of the claims 1 to 7, characterized in that it further comprises
at least one member selected from the group consisting of a surfactant, a thickening
agent, a buffer, a coloring agent, a fragrance, and mixtures thereof.
9. A composition according to claim 8, characterized in that said surfactant is at least
one member selected from the group consisting of a alkyl benzene sulfonate, an alkylether
ethoxylate, an alkylether sulfate, an amine oxide, and mixtures thereof and present
in said composition in the range from about 0.25 to about 25 % by weight.
10. A composition according to claim 8, characterized in that said thickening agent is
a polyacrylic acid, polymer or copolymer and present in said composition in the range
from 0.25 to 2.0 % by weight.
11. A method for cleaning surfaces comprising applying an effective amount of an alkaline
solution containing the phosphorus-free and boron-free cleaning composition according
to any of the claims 1 to 10.
12. A method for bleaching cloth and stain removal comprising applying an effective amount
of an alkaline solution containing the phosphorus-free and boron-free cleaning composition
according to any of the claims 1 to 10.